How to check result set empty or null in linq????

Mukesh Kumar Tiwari

13y23.6kLINQ

hey frnds ...

i have a query in linq like this.

var res = from UM in linq.AG_User_Masters

where UM.Login_id == txt_loginname.Text

select UM;

now i have to check that res contain any result or not..

but i do not getting this abjectly...

so pls help...

Thanks....

5 Replies

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Jaganathan Bantheswaran13y ago
Accepted answer
Hi,

The res never be null. The linq query will return the IEnumerable.

So you have to check like

if(res.Count > 0)
{
// do something
}
0
Vivek Kumar11y ago
Hi,

I have tried all of mentioned approaches but once you try to initiate a method on empty output of LINQ query, it will throw exception.

The best way is to check:
if(res.AsDataView().ToTable.Rows.Count==0)
{
//your code goes here
}

Thanks,
Vivek
0
Jaganathan Bantheswaran13y ago
Hi,

As Jignesh Trivedi's reply, Assign it to the property. It should work.

Let us know if you have doubts.
0
Jignesh Trivedi13y ago
hi,
here i have some suggetion...
use
if (res!=null && res.Count() > 0 )
{
     return 1;
}
else
{
     return 0;
}
also try...
var grid_data = from AG_User_Master in linq.AG_User_Masters
where AG_User_Master.user_name.Contains(@txt_search.Text)
select new
{
    Name = AG_User_Master.user_name,
    Login = AG_User_Master.Login_id,
    Role = AG_User_Master.Role,
    password = AG_User_Master.password,
    mydate = AG_User_Master.c_Date,
};
dataGridView1.DataSource = grid_data;
hope this will help you.
0
Mukesh Kumar Tiwari13y ago
if (res.Count() > 0 )
{
return 1;
}
else
{
return 0;
}
sir this is working..and
thanks for lead me......
and one more problem is there

var grid_data = from AG_User_Master in linq.AG_User_Masters
where AG_User_Master.user_name.Contains(@txt_search.Text)
select new
{
AG_User_Master.user_name,
AG_User_Master.Login_id,
AG_User_Master.Role,
AG_User_Master.password,
AG_User_Master.c_Date, //Error is at this point
};

dataGridView1.DataSource = grid_data;

Error mes is like this: unable to cat object of type System.DateTIme to type system.string
0